Although the size of portable electronic devices continues to shrink, their energy requirements often do not comparably decrease. For example, a next-generation MEMS accelerometer may have a volume that is 10 percent smaller and yet, require are only 5 percent less power than the prior generation MEMS accelerometer. In that case, more of the MEMS die may be used for energy storage. Undesirably, this trend can limit miniaturization and applicability of such electronic devices.
The art has responded to this problem by developing chip-level super-capacitors (also known as “micro super-capacitors”), which have much greater capacitances than conventional capacitors. Specifically, when compared to conventional capacitors and batteries, super-capacitors generally have higher power densities, shorter charging and discharging times, longer life cycles, and faster switching capabilities.
Super-capacitors sometimes have two closely spaced electrodes that can short circuit if contact is made. Although the prior art positions an insulative separator between the electrodes to avoid this problem, many such separators cause other problems.